1. FIELD OF THE INVENTION
The present invention relates to a light shutter means for forming images and more particularly to a light shutter means including a plurality of shutter elements aligned in arrays and defined three-dimensionally on a chip made of an electro-optical material, with the elements being disposed on both sides of a common electrode.
2. DESCRIPTION OF RELATED ARTS
A known light shutter means commonly used and commercially available is a flat face electrode type including a board type body made of such an electro-optical material as PLZT with an electrode pattern being formed on its surface.
The known light shutter means has the disadvantages of a high driving voltage, tendency to function erroneously because of cross talk attributable to interelectrode capacitance between an adjacent pair of electrodes and also of slow response.
With a view to the above problems, the prior art such as a Japanese Laid-Open Patent Publication No. 60-159722 suggested a so-called parallel electric-field type light shutter means having a plurality of three-dimensionally formed shutter elements aligned in arrays and electrodes disposed on an opposing face.
With the above light shutter means, however, because of the relatively long distance between the respective three-dimensional shutter elements, if the array is used in an optical printer, the inter-dot distance is also enlarged thereby deteriorating dot continuity or density. In short, there still remains room for improvement in its image quality.
The present inventor disclosed in his related prior application various light shutter means including a plurality of shutter elements aligned in arrays and defined three-dimensionally on a chip made of an electro-optical material, with the elements being disposed on both sides of a common electrode, and also suggested that a high quality image is obtainable through adjustment of print timings of each array for the purpose of decreasing the inter-dot distance.
Then, for driving such light shutter means, it is necessary to connect independent electrodes of respective shutter elements and a common electrode between an adjacent element array pair with an external circuit, respectively.
However, the problem remains that it is very difficult to extend a lead line from the narrow common electrode disposed at the small space between the array pair so as to connect the same with the external circuit.
Further, if a plurality of light shutter means of the above-described type are used in alignment as a printing head of an optical printer, the common electrodes of respective arrays need be connected one by one with the external circuit. Since such connections are even more difficult, there tend to occur insufficient or improper connections between the common electrodes, which result in unstable driving of the printer head.